Functional status refers to the capacity of an individual to perform or undertake actions or activities deemed essential for independent living and physiological sustenance. Clinical data in computable formats representing functional status of patients is in increasing demand for healthcare intervention impact measurement and to gauge quality of life. Functional status data is important in supporting clinical decisions affecting the individual patient and vulnerable populations such as the elderly, and those with diseases having a pervasive impact to ones life. Arthritis represents a focused clinical domain where functional status data is frequently encountered and gathered. While included in established and evolving health terminologies, efforts at formalizing functional status representation are hampered by the lack of an organizing domain ontology and the challenge of supporting fined grained patient descriptions. The newly adopted WHO International Classification of Functioning (WHO ICF) presents a potential organizing hierarchy for functional status representation. The ICF ontology and its rubrics, enhanced through the "Semantic Frames" approach for corpus driven discovery, understanding, and specification of functional status-expression semantic structures will be used as foundation upon which to build a robust functional status terminology for representation of functional status concepts important in arthritis related clinical scenarios. Our aims are to show that the WHO CF provides a useful high-level ontology for functional status data representation in arthritis related scenarios and that ICF rubrics augmented by functional status semantic frames derived from a corpus driven semantic frames approach can enable fine-grained machineable functional status data representation. Our efforts, findings, and deliverables are intended to support a long-term objective of functional status terminology development that can be extended to other clinical domains and will be synergistic with broader efforts to enable clinical data interchange and interoperability.